1. Field of the Invention
The present invention relates to a magnetic force detecting semiconductor (semiconductor magnetometry) device, for example, a magnetoelectric converting device or a magnetoresistive element and a method for manufacturing the same, and, more particularly, the shape of a magnetic resin layer to be coated on a chip for improvement of the sensitivity and a method for shaping the layer.
2. Description of the Related Art
A conventional Hall element is, as shown in FIG. 1, are formed by mounting a magnetic force detecting element chip 2 on an island 1 of a lead frame, coupling the electrodes of the chip 2 to lead terminals 3-6 by metal wires 7, and forming a mold 9 of resin. In order to strengthen the magnetic field acting on an active layer of chip 2 to improve the sensitivity of the Hall element, a magnetic resin layer 8 shown in FIG. 2 is generally formed on element chip 2. This resin layer 8 is formed by coating, and hardening, a magnetic resin on chip 2 in a hemisphere (or dome) shape, its height being about 0.5 times the length of one side of chip 2.
Conventionally, magnetic resin layer 8 essentially consists of a mixture of an epoxy resin and a soft magnetic powder. However, the thermal expansion coefficient of the epoxy resin differs significantly from that of chip 2, and in the conventional device, force is applied on chip 2 due to the stress generated by the hardening of the epoxy resin or the heat cycle after the hardening process. This increases the unbalanced voltage of the Hall element, thus deteriorating the characteristic, such as setting the output voltage not in proportion to the input current.